• Journal of the Korean Society for Aviation and Aeronautics
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• v.24 no.1
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• pp.33-40
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• 2016

ROK issued its first type certificate to the KC-100 airplane, Part 23 normal category, and become the State of Design (SoD) in 2013. Before this, ROK aviation regulations were focused on the operation and continued airworthiness of aircraft registered and operated in ROK that were designed and manufactured in another contracting state. Therefore the implementation of reporting system were restricted to gather the failure and service difficulty reports from the owners or operators and transmit the information to the State of Design and/or the manufacture relating to the type certificated aircraft. However, ROK, to fulfill the accountability of the State of Design, has to ensure there is a system to address the information received from the State of Registry on failure, malfunctions, defects and other occurrences that might cause adverse effects on the continuing airworthiness of the korean type certificated aircraft. This paper presents an overview of ICAO requirements for the State of Design, and current implementation of reporting system of USA and Japan and discusses the current status and further considerations on the rule-making for the malfunction, defect and failure reporting system applicable to the korean indigenous aircraft.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2003.10a
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• pp.333-339
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• 2003

Recently, the bridges become greater according to development of a construction technology. This phenomenon requires long span bridge, so that increases the dead weight. The orthotropic steel deck bridges have much advantages such as the light dead weight and the reduction of construction period. And almost whole process of carried out is manufactured at factory, so it can cause the increase of quality authoritativeness. But orthotropic steel deck bridge is consist of structure by welding, it can not avoid a lot of welding jobs, defects and transformation by welding are becoming problem accordingly. Specially, topical stress concentration phenomenon in cross connection area of longitudinal and transverse rib causes fatigue failure. The Bulkhead Plate for prevention of this stress concentration phenomenon was applied by changing the orthotropic steel deck of Williamsburg bridge in USA. But, it is principle that a Bulkhead Plate is not established in the domestic design standard. Therefore, it is estimated that the study for installation of Bulkhead Plate is needed. This treatise with considering these circumstances proves efficiency of Bulkhead Plate and will be presented optimal design details through finite element analysis according to change the geometrical of Bulkhead Plate and tile cross-connection area of longitudinal and transverse rib.

• Journal of the Korean Society for Railway
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• v.16 no.2
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• pp.93-98
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• 2013

Railway system is today the most efficient way for transportation in many cases in several forms of application. Yet, wear phenomenon, profile evolution, fatigue, fracture, derailment are the major worries (financial and safety) in this system which force significant direct and indirect maintenance costs. To improve the cyclic maintenance procedures and the safety issues, it can be very satisfactory to be informed of the state of wheel/rail interaction with mileage. In present paper, an investigation of the behavior of the shear stresses by logged distance is approached, by implementing the field measurement procedure, in order to determine the real conduct of the most important cause of defects in wheel/rail contact, shear stress. The results coming from a simulation procedure indicate that the amounts of shear stresses are still in high-magnitudes when the wheel and rail are completely worn; even though in simulation based on the laboratory measurements of profile evolutions, the stresses become significantly reduced by logged distance.

• Journal of the Korean institute of surface engineering
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• v.35 no.2
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• pp.129-137
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• 2002

The purpose of solderability assessment is to predict the effectiveness of soldering process. It is important for companies pursuing zero defects manufacturing because poor solderability is the major cause of two third of soldering failures. The most versatile solderability method is wetting balance method. However, there exist so many indices for wettability in the wetting balance test e.g. time to reach 2/3 values of maximum wetting force, tine to reach zero wetting force, maximum withdrawal force. In this study, three solderability assessment methods, which were the maximum withdrawal force, the wetting balance and the dynamic contact angle (DCA), were evaluated by comparing each other. The wetting balance technique measures the solderability by recording the forces exerted from the specimen after being dipped into the molten solder. Then the force at equilibrium state can be used to calculate a contact angle, which is known as static contact angles. The DCA measures contact angles occurred during advancing and withdrawing of the specimen and the contact angles are known as dynamic contact angles. The maximum withdrawal force uses the maximum force during withdrawal movement and then a contact angle can be calculated. In this study, the maximum withdrawal force method was found to be an objective index for measuring the solderability and the experiment results indicated good agreement between the maximum withdrawal force and the wetting balance method.

• International conference on construction engineering and project management
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• 2022.06a
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• pp.784-791
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• 2022

Tack coat is a thin layer of asphalt between the existing pavement and asphalt overlay. During construction, insufficient tack coat layering can later cause surface defects such as slippage, shoving, and rutting. This paper proposed a method for tack coat inspection improvement using an unmanned aerial vehicle (UAV) and deep learning neural network for automatic non-uniform assessment of the applied tack coat area. In this method, the drone-captured images are exploited for assessment using a combination of Mask R-CNN and Grey Level Co-occurrence Matrix (GLCM). Mask R-CNN is utilized to detect the tack coat region and segment the region of interest from the surroundings. GLCM is used to analyze the texture of the segmented region and measure the uniformity and non-uniformity of the tack coat on the existing pavements. The results of the field experiment showed both the intersection over union of Mask R-CNN and the non-uniformity measured by GLCM were promising with respect to their accuracy. The proposed method is automatic and cost-efficient, which would be of value to state Departments of Transportation for better management of their work in pavement construction and rehabilitation.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.49 no.5
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• pp.304-307
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• 2023

Venous malformation (VM) is a benign lesion of blood vessels caused by an error in vascular morphogenesis during the embryologic phase. This entity mostly affects the head and neck region, including the lips, tongue, buccal mucosa, gingiva, or palate. VM may cause functional and aesthetic impairments. The anatomical structure and shape of the lips provide an important aesthetic accent for an individual. Therefore, management of VM in the lip area without postoperative defects or scarring is challenging. In this brief communication article, we present a conservative approach to lip VM in a nine-year-old boy using a bleomycin injection that had good aesthetic and functional outcomes. Injection of 2 mL of 1/10 of 15 mg bleomycin in a saline dilution into the lip mucosa may present a drug reaction as a white plaque and reddish owl eye lesion that takes up to three weeks to resolve without a scar. It is important to recognize the characteristics and self-limiting nature of postoperative bleomycin complications to avoid unnecessary treatment.

• Nuclear Engineering and Technology
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• v.56 no.6
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• pp.2071-2078
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• 2024

The precipitation of solutes is a major cause of irradiation hardening and embrittlement limiting the service life of reactor pressure vessel (RPV) steels. Impurities play a significant role in the formation of precipitation in RPV materials. In this study, the effects of carbon on cluster formation and irradiation hardening were investigated in an RPV alloy Fe-1.35Mn-0.75Ni using C and Fe ions irradiation at 290 ℃. Nanoindentation results showed that C ion irradiation led to less hardening below 1.0 dpa, with hardening continuing to increase gradually at higher doses, while it was saturated under Fe ion irradiation. Atom probe tomography revealed a broad size distribution of Ni-Mn clusters under Fe ion irradiation, contrasting a narrower size distribution of small Ni-Mn clusters under C ion irradiation. Further analysis indicated the influence of carbon on the cluster formation, with solute-precipitated defects dominating under C ion irradiation but interstitial clusters dominating under Fe ion irradiation. Simulations suggested that carbon significantly affected solute nucleation, with defect clusters displaying smaller size and higher density as carbon concentration increased. The higher hardening at doses above 1.0 dpa was attributed to a substantial increase in the number density of defect clusters when carbon was present in the matrix.

• Journal of the Semiconductor & Display Technology
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• v.10 no.3
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• pp.15-19
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• 2011

The performance of the DRAM is strongly dependent on the purity and surface roughness of the TIT (TiN/Insulator/ TiN) capacitor electrodes. Hence, in the present study, we evaluate the effects of organic contamination and change of surface roughness on the cylindrical TIT capacitor electrodes during the wet cleaning process by various analytical techniques such as TDMS, AFM, XRD and V-SEM. Once the sacrificial oxide and PR (Photo Resist) are removed by HF, the organic contamination and surface oxide films on the bottom Ti/TiN electrode become visible. With prolonged HF process, the surface roughness of the electrode is increased, whereas the amount of oxidized Ti/TiN is reduced due to the HF chemicals. In the 80nm DRAM device fabrication, the organic contamination of the cylindrical TIT capacitor may cause defects like SBD (Storage node Bridge Defect). The SBD fail bit portion is increased as the surface roughness is increased by HF chemicals reactions.

• Steel and Composite Structures
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• v.20 no.2
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• pp.357-378
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• 2016

The progressive collapse phenomenon in structures has been interested by civil engineers and the building standards organizations. This is particularly true for the tall and special buildings ever since local collapse of the Ronan Point tower in UK in 1968. When initial or secondary defects of main load carrying elements, overloads or unpredicted loads occur in the structure, a local collapse may be arise that could be distributed through entire structure and cause global collapse. One is not able to prevent the reason of failure as well as the prevention of propagation of the collapse. Also, one is not able to predict the start point of collapse. Therefore we should generalize design guides to whole or the part of structure based on the risk analysis and use of load carrying elements removal scenario. There are some new guides and criteria for elements and connections to be designed to resist progressive collapse. In this paper, codes and recommendations by various researchers are presented, classified and compared for steel structures. Two current design methods are described in this paper and some retrofitting methods are summarized. Finally a steel building with special moment resistant frame is analyzed as a case study based on two standards guidelines. This includes consideration of codes recommendations. It is shown that progressive collapse potential of the building depends on the removal scenario selection and type of analysis. Different results are obtained based on two guidelines.

• BMB Reports
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• v.52 no.10
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• pp.619-624
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• 2019

The primary cilium is a microtubule-based structure projecting from a cell. Although the primary cilium shows no motility, it can recognize environmental stimuli. Thus, ciliary defects cause severe abnormalities called ciliopathies. Ciliogenesis is a very complex process and involves a myriad of components and regulators. In order to excavate the novel positive regulators of ciliogenesis, we performed mRNA microarray using starved NIH/3T3 cells. We selected 62 murine genes with corresponding human orthologs, with significantly upregulated expression at 24 h after serum withdrawal. Finally, calpain-6 was selected as a positive regulator of ciliogenesis. We found that calpain-6 deficiency reduced the percentage of ciliated cells and impaired sonic hedgehog signaling. It has been speculated that this defect might be associated with decreased levels of ${\alpha}-tubulin$ acetylation at lysine 40. This is the first study to report a novel role of calpain-6 in the formation of primary cilia.